One of the many benefits of producing a document by computer is the ability to quickly and easily modify the document, and print out several revisions before deciding on the final version. Also convenient is the ability of a computer or a digital copier to produce multiple copies for distribution to and review by many people.
While interim printed and copied drafts of a document are useful, production of such may dramatically increase the overall cost of the final document, as each copy of the document produced requires additional consumable materials, such as print media and paper. The cost of each copy of a document produced can be reduced by reducing the consumables used.
One method of reducing the cost of the print media required by a printer or a digital copier is to use less of it for each copy of the document produced. For an ink jet printer, this may mean using less ink to form the images on the paper, and for a laser printer or digital copier it may mean using less toner to form the images.
The amount of media that is used to form an image may be reduced by adjusting the method by which the image is formed. For example, in portions of the image where a solid, unbroken field of media would typically be applied, an intermittent pattern of media and unprinted areas could be used. Various methods for reducing the print media are available. One such technology may be termed graying, and may be used not only to conserve media, but to approximate gray areas on a printed page.
Different graying methods have been used to reduce the amount of media required to print an image. For example, all of the portions of an image which would usually be solidly covered by media could have a gray pattern applied to them. Thus, those portions that would have otherwise been solidly covered with media, now only require a fraction of that amount of media. The amount of media saved depends on the density of the gray pattern used, or in other words, the ratio of printed and unprinted areas in the gray pattern. Another method would be to apply the gray pattern to only some portions of the image, and solid media to other portions. This latter method can be especially useful for images such as letters and other alphanumeric characters.
Letters which are printed by forming a solid border of media at the outside edge of the character, and then filled in with a gray pattern of media, may be easier to read than those characters which are completely formed of a gray pattern of media. Legibility of the font at different sizes tends to be affected by the width of the solid border, and the density of the gray pattern. However, these parameters are typically not adjustable in current technology devices.
Further, as image size decreases, the solid border of an image comprises a greater portion of the image, and there is less space inside the image for a gray pattern. For such images an interior gray pattern does not offer much of a savings in print media.